/* Copyright  (c) 2002 Graz University of Technology. All rights reserved.
 *
 * Redistribution and use in  source and binary forms, with or without 
 * modification, are permitted  provided that the following conditions are met:
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 * 1. Redistributions of  source code must retain the above copyright notice,
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 *
 * 2. Redistributions in  binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  
 * 3. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment:
 * 
 *    "This product includes software developed by IAIK of Graz University of
 *     Technology."
 * 
 *    Alternately, this acknowledgment may appear in the software itself, if 
 *    and wherever such third-party acknowledgments normally appear.
 *  
 * 4. The names "Graz University of Technology" and "IAIK of Graz University of
 *    Technology" must not be used to endorse or promote products derived from 
 *    this software without prior written permission.
 *  
 * 5. Products derived from this software may not be called 
 *    "IAIK PKCS Wrapper", nor may "IAIK" appear in their name, without prior 
 *    written permission of Graz University of Technology.
 *  
 *  THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
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package iaik.pkcs.pkcs11.objects;

import iaik.pkcs.pkcs11.Session;
import iaik.pkcs.pkcs11.TokenException;
import iaik.pkcs.pkcs11.wrapper.Constants;
import iaik.pkcs.pkcs11.wrapper.PKCS11Constants;
import iaik.pkcs.pkcs11.wrapper.PKCS11Exception;



/**
 * This is the base class for hardware feature classes. Objects of this class
 * represent hardware features as specified by PKCS#11 v2.20.
 * A hardware feature is of a specific type: MONOTONIC_COUNTER, CLOCK,
 * CKH_USER_INTERFAC or VENDOR_DEFINED. 
 * If an application needs to use vendor-defined hardware
 * features, it must set a VendorDefinedHardwareFeatureBuilder using the
 * setVendorDefinedHardwareFeatureBuilder method.
 *
 * @author Karl Scheibelhofer
 * @version 1.0
 * @invariants (hardwareFeatureType_ <> null)
 */
public class HardwareFeature extends Object {

  /**
   * This interface defines the available hardware feature types as defined by
   * PKCS#11 2.20: MONOTONIC_COUNTER, CLOCK, CKH_USER_INTERFAC or VENDOR_DEFINED.
   *
   * @author Karl Scheibelhofer
   * @version 1.0
   * @invariants
   */
  public interface FeatureType {

    /**
     * The indentifier for a monotonic counter.
     */
    static public final Long MONOTONIC_COUNTER = new Long(PKCS11Constants.CKH_MONOTONIC_COUNTER);

    /**
     * The indentifier for a clock.
     */
    static public final Long CLOCK = new Long(PKCS11Constants.CKH_CLOCK);

    /**
     * The indentifier for a user interface.
     */
    static public final Long USER_INTERFACE = new Long(PKCS11Constants.CKH_USER_INTERFACE);

    /**
     * The indentifier for a VENDOR_DEFINED hardware feature. Any Long object
     * with a value bigger than this one is also a valid vendor-defined hardware
     * feature type identifier.
     */
    static public final Long VENDOR_DEFINED = new Long(PKCS11Constants.CKH_VENDOR_DEFINED);

  }

  /**
   * If an application uses vendor defined hardware features, it must implement
   * this interface and install such an object handler using
   * setVendorDefinedHardwareFeatureBuilder.
   *
   * @author Karl Scheibelhofer
   * @version 1.0
   * @invariants
   */
  public interface VendorDefinedHardwareFeatureBuilder {

    /**
     * This method should instanciate an Object of this class or of any
     * sub-class. It can use the given handles and PKCS#11 module to retrieve
     * attributes of the PKCS#11 object from the token.
     *
     * @param session The session to use for reading attributes.
     *                This session must have the appropriate rights; i.e.
     *                it must be a user-session, if it is a private object.
     * @param objectHandle The object handle as given from the PKCS#111 module.
     * @return The object representing the PKCS#11 object.
     *         The returned object can be casted to the
     *         according sub-class.
     * @exception PKCS11Exception If getting the attributes failed.
     * @preconditions (session <> null)
     * @postconditions (result <> null) 
     */
    public Object build(Session session, long objectHandle) throws PKCS11Exception;

  }

  /**
   * The currently set vendor defined hardware feature builder, or null.
   */
  protected static VendorDefinedHardwareFeatureBuilder vendorHardwareFeatureBuilder_;

  /**
   * The type of this hardware feature. Its value is one of FeatureType, or one
   * that has a bigger value than VENDOR_DEFINED.
   */
  protected HardwareFeatureTypeAttribute hardwareFeatureType_;

  /**
   * The default constructor. An application use this constructor to instanciate
   * a hardware feature that serves as a template. It may also be useful for
   * working with vendor-defined hardware features.
   *
   * @preconditions
   * @postconditions
   */
  public HardwareFeature() {
    super();
    objectClass_.setLongValue(ObjectClass.HW_FEATURE);
  }

  /**
   * Called by getInstance to create an instance of a PKCS#11 hardware feature.
   * 
   * @param session The session to use for reading attributes.
   *                This session must have the appropriate rights; i.e.
   *                it must be a user-session, if it is a private object.
   * @param objectHandle The object handle as given from the PKCS#111 module.
   * @exception TokenException If getting the attributes failed.
   * @preconditions (session <> null)
   * @postconditions
   */
  protected HardwareFeature(Session session, long objectHandle)
      throws TokenException
  {
    super(session, objectHandle);
    objectClass_.setLongValue(ObjectClass.HW_FEATURE);
  }

  /**
   * Get the given hardware feature type as string.
   *
   * @param hardwareFeatureType The hardware feature type to get as string.
   * @return A string denoting the object hardware feature type; e.g. "Clock".
   * @preconditions (hardwareFeatureType <> null)
   * @postconditions (result <> null) 
   */
  public static String getHardwareFeatureTypeName(Long hardwareFeatureType) {
    String hardwareFeatureTypeName;

    if (hardwareFeatureType == null) {
      throw new NullPointerException("Argument \"hardwareFeatureType\" must not be null.");
    }
    
    if (hardwareFeatureType.equals(FeatureType.MONOTONIC_COUNTER)) {
      hardwareFeatureTypeName = "Monotonic Counter";
    } else if (hardwareFeatureType.equals(FeatureType.CLOCK)) {
      hardwareFeatureTypeName = "Clock";
    } else if (hardwareFeatureType.equals(FeatureType.USER_INTERFACE)) {
      hardwareFeatureTypeName = "User Interface";
    } else if ((hardwareFeatureType.longValue() & FeatureType.VENDOR_DEFINED.longValue()) != 0L) {
      hardwareFeatureTypeName = "Vendor Defined";
    } else {
      hardwareFeatureTypeName = "<unknown>";
    }

    return hardwareFeatureTypeName ;
  }

  /**
   * Called by sub-classes to create an instance of a PKCS#11 hardware feature.
   * This method reads the hardware feature type attribute and calls the
   * getInstance method of the according sub-class.
   * If the hardware feature type is a vendor defined it uses the
   * VendorDefinedHardwareFeatureBuilder set by the application. If no hardware
   * feature could be constructed, this method returns null.
   *
   * @param session The session to use for reading attributes.
   *                This session must have the appropriate rights; i.e.
   *                it must be a user-session, if it is a private object.
   * @param objectHandle The object handle as given from the PKCS#111 module.
   * @return The object representing the PKCS#11 object.
   *         The returned object can be casted to the
   *         according sub-class.
   * @exception TokenException If getting the attributes failed.
   * @preconditions (session <> null)
   * @postconditions (result <> null) 
   */
  public static Object getInstance(Session session, long objectHandle)
      throws TokenException
  {
    if (session == null) {
      throw new NullPointerException("Argument \"session\" must not be null.");
    }
    
    HardwareFeatureTypeAttribute hardwareFeatureTypeAttribute = new HardwareFeatureTypeAttribute();
    getAttributeValue(session, objectHandle, hardwareFeatureTypeAttribute);
    
    Long hardwareFeatureType = hardwareFeatureTypeAttribute.getLongValue();
 
    Object newObject;

    if (hardwareFeatureTypeAttribute.isPresent() && (hardwareFeatureType != null)) {
      if (hardwareFeatureType.equals(FeatureType.MONOTONIC_COUNTER)) {
        newObject = MonotonicCounter.getInstance(session, objectHandle);
      } else if (hardwareFeatureType.equals(FeatureType.CLOCK)) {
        newObject = Clock.getInstance(session, objectHandle);
      } else if (hardwareFeatureType.equals(FeatureType.USER_INTERFACE)) {
        // TODO: add user interface object
        // newObject = UserInterface.getInstance(session, objectHandle);
        newObject = getUnknownHardwareFeature(session, objectHandle);        
      } else if ((hardwareFeatureType.longValue() & FeatureType.VENDOR_DEFINED.longValue()) != 0L) {
        newObject = getUnknownHardwareFeature(session, objectHandle);
      } else {
        newObject = getUnknownHardwareFeature(session, objectHandle);
      }        
    } else {
      newObject = getUnknownHardwareFeature(session, objectHandle);
    }

    return newObject ;
  }

  /**
   * Try to create a hardware feature which has no or an unkown harware feature 
   * type attribute.
   * This implementation will try to use a vendor defined hardware feature
   * builder, if such has been set. 
   * If this is impossible or fails, it will create just
   * a simple {@link iaik.pkcs.pkcs11.objects.HardwareFeature HardwareFeature}.
   * 
   * @param session The session to use.
   * @param objectHandle The handle of the object
   * @return A new Object.
   * @throws TokenException If no object could be created.
   * @preconditions (session <> null)
   * @postconditions (result <> null)
   */
  protected static Object getUnknownHardwareFeature(Session session, long objectHandle) 
      throws TokenException
  {
    if (session == null) {
      throw new NullPointerException("Argument \"session\" must not be null.");
    }
    
    Object newObject;    
    if (vendorHardwareFeatureBuilder_ != null) {
      try {
        newObject = vendorHardwareFeatureBuilder_.build(session, objectHandle);
      } catch (PKCS11Exception ex) {
        // we can just treat it like some unknown type of hardware feature
        newObject = new HardwareFeature(session, objectHandle);
      }
    } else {
      // we can just treat it like some unknown type of hardware feature
      newObject = new HardwareFeature(session, objectHandle);
    }
    
    return newObject ;
  }

  /**
   * Set a vendor-defined hardware feature builder that should be called to
   * create an* instance of an vendor-defined PKCS#11 hardware feature; i.e.
   * an instance of a vendor defined sub-class of this class.
   *
   * @param builder The vendor-defined hardware feature builder. Null to clear
   *                any previously installed vendor-defined builder.
   * @preconditions
   * @postconditions
   */
  public static void setVendorDefinedHardwareFeatureBuilder(VendorDefinedHardwareFeatureBuilder builder) {
    vendorHardwareFeatureBuilder_ = builder;
  }

  /**
   * Get the currently set vendor-defined hardware feature builder.
   *
   * @return The currently set vendor-defined hardware feature builder or null
   *         if none is set.
   * @preconditions
   * @postconditions
   */
  public static VendorDefinedHardwareFeatureBuilder getVendorDefinedHardwareFeatureBuilder() {
    return vendorHardwareFeatureBuilder_ ;
  }

  /**
   * Put all attributes of the given object into the attributes table of this
   * object. This method is only static to be able to access invoke the
   * implementation of this method for each class separately (see use in
   * clone()).
   *
   * @param object The object to handle.
   * @preconditions (object <> null)
   * @postconditions
   */
  protected static void putAttributesInTable(HardwareFeature object) {
    if (object == null) {
      throw new NullPointerException("Argument \"object\" must not be null.");
    }

    object.attributeTable_.put(Attribute.HW_FEATURE_TYPE, object.hardwareFeatureType_);
  }

  /**
   * Allocates the attribute objects for this class and adds them to the
   * attribute table.
   *
   * @preconditions
   * @postconditions
   */
  protected void allocateAttributes() {
    super.allocateAttributes();

    hardwareFeatureType_ = new HardwareFeatureTypeAttribute();

    putAttributesInTable(this);
  }

  /**
   * Create a (deep) clone of this object.
   *
   * @return A clone of this object.
   * @preconditions
   * @postconditions (result <> null)
   *                 and (result instanceof HardwareFeature)
   *                 and (result.equals(this))
   */
  public java.lang.Object clone() {
    HardwareFeature clone = (HardwareFeature) super.clone();

    clone.hardwareFeatureType_ = (HardwareFeatureTypeAttribute) this.hardwareFeatureType_.clone();

    putAttributesInTable(clone); // put all cloned attributes into the new table

    return clone ;
  }

  /**
   * Compares all member variables of this object with the other object.
   * Returns only true, if all are equal in both objects.
   *
   * @param otherObject The other object to compare to.
   * @return True, if other is an instance of this class and all member
   *         variables of both objects are equal. False, otherwise.
   * @preconditions
   * @postconditions
   */
  public boolean equals(java.lang.Object otherObject) {
    boolean equal = false;

    if (otherObject instanceof HardwareFeature) {
      HardwareFeature other = (HardwareFeature) otherObject;
      equal = (this == other)
              || (super.equals(other)
                  && this.hardwareFeatureType_.equals(other.hardwareFeatureType_));
    }

    return equal ;
  }

  /**
   * Gets the hardware feature type attribute of the PKCS#11 key. Its value
   * must be one of those defined in the FeatureType interface or one with an
   * value bigger than FeatureType.VENDOR_DEFINED.
   *
   * @return The hardware feature type identifier.
   * @preconditions
   * @postconditions (result <> null)
   */
  public LongAttribute getHardwareFeatureType() {
    return hardwareFeatureType_ ;
  }

  /**
   * The overriding of this method should ensure that the objects of this class
   * work correctly in a hashtable.
   *
   * @return The hash code of this object.
   * @preconditions
   * @postconditions
   */
  public int hashCode() {
    return hardwareFeatureType_.hashCode() ;
  }

  /**
   * This method returns a string representation of the current object. The
   * output is only for debugging purposes and should not be used for other
   * purposes.
   *
   * @return A string presentation of this object for debugging output.
   * @preconditions
   * @postconditions (result <> null)
   */
  public String toString() {
    StringBuffer buffer = new StringBuffer(128);

    buffer.append(super.toString());

    buffer.append(Constants.NEWLINE);
    buffer.append(Constants.INDENT);
    buffer.append("Hardware Feature Type: ");
    if (hardwareFeatureType_ != null) {
      buffer.append(hardwareFeatureType_.toString());
    } else {
      buffer.append("<unavailable>");
    }

    return buffer.toString() ;
  }

}
